Oh, for what it's worth, DHCP rarely fails completely for me (Netgear 100BaseTX 8port switch). It sometimes takes a retry or 2.

I reckon that it's got something to do with the switch autosensing the line speed taking longer than the empeg is willing to wait. In most other platforms the time between plumbing the interface and requesting an IP is probably longer.
If this is the case, I wonder if hijack could plumb the interface and send a dummy packet out earlier, thus forcing the switch to autosense earlier.